Lua HMAC authentication

install-openresty.sh

$ brew tap killercup/homebrew-openresty
$ brew install ngx_openresty

openresty-auth-nginx.lua

location / {
    access_by_lua '
        if ngx.var.http_x_auth_token ~= "Your Secret Token" then
            return ngx.exit(401)
        end
    ';
    proxy_pass http://your-upstream;
}

openresty-hmac-nginx.lua

init_by_lua '
	crypto = require("crypto")
';

location / {
	lua_need_request_body on;
	access_by_lua '
		access_key = ngx.var.http_x_access_key_id
		secret_key = some_method_that_looks_up_a_secret_key(access_key)
		local hmac = crypto.hmac.digest("sha1", ngx.req.get_body_data(), secret_key)
		
		if hmac ~= ngx.var.http_x_request_hmac then
			 return ngx.exit(401)
		end
	';
	proxy_pass http://your-upstream;
}